Hypereosinophilic Syndrome

Diagnosis

A diagnosis of hypereosinophilic syndrome (HES) is based on persistently high levels of eosinophils in the blood and evidence of organ damage. Your healthcare professional will ask about your symptoms, family medical history, medications, and possible exposure to infections or allergens.

To confirm the diagnosis, tests are performed to determine the cause of elevated eosinophils and assess whether any organs have been affected.

Tests to determine the cause include:

• Blood tests to identify autoimmune diseases, infections, or blood-related cancers.

• Allergy tests to detect sensitivities to environmental or food allergens.

• Stool tests to check for parasitic infections such as hookworm.

• Genetic tests to identify rare gene mutations that may lead to HES.

• Bone marrow samples to detect cancers or bone marrow disorders.

Tests to assess organ damage include:

• Blood tests to evaluate liver and kidney function.

• Imaging tests to study organ structure and performance.

• Echocardiogram to assess heart health.

• Lung function tests to measure breathing capacity.

• Tissue samples from organs to check for eosinophil buildup or tissue injury.

These diagnostic steps help determine the extent of the condition and guide the most effective treatment approach.

Treatment

Treatment for HES focuses on reducing eosinophil levels, managing symptoms, and preventing further organ damage. When an underlying cause is identified, that condition is treated as well.

Medicines commonly used include:

• Corticosteroids, which are the first line of treatment to reduce circulating eosinophils.

• Hydroxyurea (Droxia, Hydrea) for patients who do not respond adequately to corticosteroids.

• Imatinib (Gleevec) for cases linked to specific genetic mutations.

• Mepolizumab (Nucala), a biologic medication that targets eosinophils.

• Vincristine PFS for severe or treatment-resistant cases.

Because hypereosinophilic syndrome can increase the risk of blood clots, blood-thinning medicines such as warfarin (Coumadin) may also be prescribed.

Early and tailored treatment helps prevent long-term organ complications and improves overall quality of life for individuals with HES.